Method of making lightweight filamentous structures



R. J. TAYLOR METHOD OF MAKING LIGHTWEIGHT 7 Feb. 8, 1949.

FILAMENTOUS STRUCTURES Filed April 12, 1944 w whw M H T m7. M V 0 o O oO o o O m W O .0. 0 o c O o o A f M Y B =1 T W Q 5 Q MN N m N 1 L 7 I IQ l Q I x 1 HI H vIH I o o o e o E E. P k p k r b 9 m [h m a oJ r0 IPatented F eb. 8, 1949 METHOD OF MAKING LIGHTWEIGHT FILAMENTOUSSTRUCTURES Robert J. Taylor, Claymont, Del., assignor to AmericanViscose Corporation, Wihnington, Del., a corporation of DelawareApplication April 12, 1944, Serial No. 530,082

Claims. 1

This invention relates to methods for the production of ribbon-like ormat-like structures having a crinkled structure. This application is acontinuation-in-part of my copending application Serial No. 479,889,filed March 20, 1943, now Patent 2,399,258, April 30, 1946, and mycopending application Serial No. 490,009, filed June 8,

1943, now Patent 2,399,260.

In general, in the present invention, a filamentary bundle containing amixture of filaments,

preferably of the same material, having different characteristics ofplasticity and/ or elasticity is produced and subjected to stretchingand relaxation. The bundle maybe ribbon-like or mat-like in character.The filamentary bundle may comprise some filaments which aresubstantially truly elastic in character and relatively free of anyplastic flow under the conditions of stretching, as well as otherfilaments which are essentially plastic in character so that thestretching effects an elongation which is substantially permanent and isnot recovered, or is only partially recovered where a partial elasticityis present, upon subsequent relaxation when the stretching forceisremoved. Upon release of the stretching force from such a bundle offilaments, the elastic filaments return to their original length byvirtue of their elasticity while the plastic filaments are caused totake a crinkled conformation because of the reduction in length of theelastic filaments.

The mixture of essentially elastic filaments with essentially plasticfilaments may be obtained in various ways. For example, one or morefilaments may be rendered plastic, such as by the application of heat,solvents, swelling or plasticizing agents, depending upon the particularmaterial of which the filaments are constituted, and they may then beassociated with one or more non-plasticized filaments ofthe same ordifferent material with or without twisting. Again, filaments which arecompletely elastic and set up may be associated with freshly spun and.still plastic filaments of the same or different material. In thislatter case, the association may occur shortly after the plasticfilaments leave the spinneret. Again, one or more filaments of smalldiameter may be spun simultaneously with one or more filaments of largediameter (which may be hollow, if desired) and passed through a commoncoagulating bath, from which the associated filaments emerge indifferent plastic and elastic conditions and are subjected to stretchingin that state. This may be accomplished by having a single spinneretcontaining both large "and small orifices, or by having a plurality ofspinnerets oneof which has large orificesand the other small orifices,from which different size filaments may be spun. Again, the same resultmaybe the orifices.

These materials may comprise difierent filamentiorming components soadjusted that upon emersion from the coagulating bath the differenttypes of filaments exhibit different characteristics of plasticity andelasticity, in which state they may be stretched. A plasticizer may beincorporated in one of the spinning materials for imparting to thefilaments obtained therefrom a rubber-like elasticity, especiallywhenvinyl resins are used. Also, the materials may comprise the samefilament-forming component but use difierent solvents which are removedfrom the extruded filaments at different rates, thus assuringdifferences in elasticity and plasticity at the time of subsequentstretching. For example, a copolymer of vinyl chloride and vinyl acetatemay be dissolved in dioxane and extruded through one spinneret, while asimilar solution in acetone which is more volatile than dioxane may beextruded through another spinneret. Thedifferences in plasticity andelasticity at the time'of stretching, in the latter system, may beaccentuated by extruding the solution in dioxane through larger holesthan those of the spinneret through which the acetone solution isextruded. As an alternative to the use of separate spinnerts in any ofthey cases just mentioned, a type. of spinneret or jet may be employedwhich'is provided with suitable partitions back of the spinneret face,for dividing that space into separate regions which communicatewithseparate lines to difierent spinning supplies entirely, or throughseparate pumps to a common spinning line, so that the spinning materialsupplied to one of the regions back of the spinneret face passes throughthe orifices associated therewith and that supplied to the otherregion'or regions back of the spinneret face is extruded through theother orifices in the spinneret, which may be of the same or ofdifferent size than the orifices associated with the other region. Thistype of spinneretis the subject matter involved in the co-pendingapplication of Robert J. Taylor and Wesley L. Webb, Serial No. 492,702,filed June ments, the small filaments will show the most crinkling inthe product. W here, however, stretching is performed upon a mixture offreshly spun filaments of both large and small diameters, the smallfilaments being completely set and the large filaments still plastic;the large filaments will show the most crinkling in the .product.

The stretching may be performed by anynf the known means heretoforeemployedfor stretching yarns or yarn-like bundles of filaments. Thus thebundle may be passed about a series of positively driven rolls insuccession, at sesame- --of said .TheseandalternatiVe arrangements areillustrativelyrepresented in the drawings hereinafter, inwhich- Figure 1is an elevation of an arrangement adapted toharidletheweb-likefilamentary bundles Figure 2 is another illustration of anarrangementfor manipulating the web-like bundles;

Figure 3 showsia cross-section of one form of spinneret that may beused; and

Figure .4 is.. a face yiewof a modified form of spinneret that maybeusedin the invention.

Eigure 1 shows .a ..eoagulating bath? with a a second funn el; guide H!is positioned in the bath near the point of emergence of the filamentstherefrom. The. filaments, in the gformcf a weblike sheet with thefilaments arranged either parallel or haphazardly intercrossed therein,proceed through a seriesofsseparate conveyor systems ll l-2, !3in.succession, and then to-a suitable take-updevicel l. onwhichthe sheetmay .be collectedwith or without tension. Each conveyor device comprisesa pair of superposed chain sections comprising :interdigitatingcross-pieces or girtslt "which seize the webrlike sheet and hold it. inzigzag coniormation while moving the sheet through the device. Thisparticular device forms no part of this invention and its constructionmaybe-that of the device disclosed in my copending application SerialNo. 530,683, filed April 12, 1944, patented October 2, 1945, No.2,385,894. The second conveyor system I2 is operated at ahigher-rate ofspeedinorder to-effect stretching of thefiight ofthe web-likesheetextending betweenthe two systems II and [2.

The web-like sheet aiterleavingthe second conveyoivsystem 'l- 2 may'.-beallowed to relax in its flight therefrom tothe nextconveyorsystem l3,which may be utilizedfor carryingthe sheet during wettreating or-dryingthereof. From the latter 'conveyorvsysteml lfi, the sheet may becontinuously transferred .-to a suitable take-up device, such'as a drumwhichmay be operated while partially immersed in a liquid, such as waterinert to thefilamentatoobtaina wound band of intricately intercrossedfilaments of the type i cles in my mien-pat nt 39 s my priorapplication, the wound band, after col- 4 lection, may be slit in thegeneral direction of its width andniay then be dried. {The dried band isthen seized at its four corners (or at numerous spaced points along eachof the two sides which extend in the same general direction as thelength of the filaments) and while maintaining it untier-tension alongits length between the points .of seizure, it is stretched out in thedirection of its width. This stretching along the width is accompanied.by a surprising expansion in the thickness of the material.

FigureZ-showsan arrangement similar to that oflzfigurel in that theobject is to produce a weblike sheet of filaments comprising both largeand small diameters. The spinneret l6 may beof .the form shown in Figure5 and the filaments pass throughguides of funnel like characters I"! andi3, then about rolls 119,10 and '21, which are arranged toenact-transfer of the welrlike sheet as a sheet out of'thecoagulatingbath 22 into a second bath23 within which the filaments maybestretched as a sheehsuch stretching being effectedby virtue of the factthat the web-like sheet passes aboutcthe peripheries of another set ofthree rollers 24, 25 and '25, driven at [higher speed than the firstset. The second setof rollers serves also to remove thev filaments as aweb-like sheet out of the second bath '23, andtolirnmerse them intoa'third bath 2'! within which they proceed through a guide 28 to asuitable take-11p device 28 whichmayhe partially immersed in the liquidof the third'bath. By maintaining the flights oi filamentsextending'between the two sets of rollers andbet'ween the second set ofvroll- .ers and thetake-up device under liquid, the loss of. the web-likecharacter of the filamentary bun die is prevented, even though subjectedto stretching during such free flights. 7

Figure'li-illustrates in cross-section a form of spinneret in which onespinning material may be extruded through certain of the orificesthereof and another spinning material extruded through certain otherorifices thereof. To accomplish the space backof the spinneret face 30is dividedbya partition 3i into two or more separate regions (two suchregions A and B being shown), each of such regions communicating with aseparate setor group .of orifices 32and 32', .whichmay .or may not .beof thesame size. iTheregionsA andBinto which the space back of the.spinneret is divided, is then associated withseparate .spinningsolutions by means of separate feed lines stand .3llrespective1y, Ofcourse, if it .ismerely desired tousea spinneret having orifices allofthe same sizeand a single spinning solutiomthe regions ,backcf thespinneret face may beconnected through the separate lines 33 ande ii andseparate pumps .to a common supply lineforthe spinning solution and thentwo pumps operated at difierentspeeds to pro- .duce differently sizedfilaments.

In Figure l the. spinneret=35 haslarge orifices 36 andsmalhorificesalheterogeneously intermingled. .The-use-of thisspinneret causes the24:1nches is capable of completely setting thesmall diameter filamentswithout destroying the elasticity of the larger filaments Spinnerets ofeither of the types shown in Figures .3 and 4 may be used in eitherofthe arrangements shown in Figures 1 and 2.

Besides producing wound bands ofcrinkled web-like filamentary sheets,expansion of. the wound bands obtained by the arrangements of Figuresland 2 in accordance with the procedure disclosed in my Patent2,399,258, produces a novel light-weight filamentous product useful as aheat insulation material, a buoyant material, for aerosol filtration,cushioning material and the like. Such products may comprise filamentshaving large diameters ranging from about microns to 300 or more micronsin diameter, and any desired proportion of small diameter filamentsranging from about 1 to 10 microns, or theymay comprise any combinationof small and large sizes. Because of the conditions and circumstancesunder which the wound bands are made in accordance with the presentinvention, the cut-.

ting of such a wound band transversely of its annulus and expansiontransverse of the width of the bandgives rise to products'in whicheither the small or the large diameterfilaments therein crinklinessbecomes more uniformly distributed throughout the product.

In general, the expanded mats made in'accordancewith this invention andthe disclosure of my prior copending application comprise criss-crossfilaments lying substantially in generally parallel and more or lessundular planes, so that the mat is substantially laminar in character.The space occupied by the mat is extremely subdivided by the criss-crossfilaments extending in undulated planes substantially at right angles tothe thickness of the mat and to the fact that the lattice work formed bythe filaments in one web is out of alignment with that in adjacent webslying generallyiparallel thereto. The extreme intricacy ofthe network isparticularly noticeable when a large number of filaments of extremelyfine diameter and a relatively small proportion of large diameterfilaments are converted into the prodnot. The superimposition of web onweb of such irregularly arranged intercrossing filaments with theadditional waviness in' the individual filaments :produces a filamentousmass having an intricate network disposed across the path of travel inthe direction of the thickness of the mat. All filaments in one web,lamination or strata do not contact all filaments in the next adjacentat the, pointswhere they appear. to crossas the result of the distortioncaused by the stretching.

th contraction caused ness and. crinkliness in those filaments whichwere in a plastic condition when the mixture was subjected to initialstretching; The result is that, while all of the filaments in theproduct extend generally from one side thereof to an opposite side; oredge'thereof, many of the filaments are infa highly crinkled conditionas the result either of...

theinitial stretching of the mixed plasticand elastic filaments or ofthe subsequent stretching:

of the'band to expand it into theform of-a mat,

or, in .some cases, as. the result of both factors. The-mats producedinaccordance with, this'in-.-.

vention are characterized-by.essentially the same structure as'in my'prior copending application,

except that amixture of diiferent sized filaments:

are involved in the present mats and either the larger. or the smallerfilaments therein or both the large and small filaments, arecharacterized by-increased waviness and .crinkliness, as-compared to themats of myearlier application.-

While preferred embodiments of the inventionhave-been disclosed, it isto be understood that changes and variations may be made withoutdeparting from the spirit and scope of the inventionas defined by theappended claims.

I claim:

prising' continuous filaments in a plastic'condition mixed withcontinuous filaments in an" elastic condition, collecting the sheet assuch' while still wet in the form of a multiple-layered" winding,severing the windin across its width, .drying the relaxedwinding in theform of a band, and stretching the dried band out in the' direction ofits width while permitting it to expand in thickness. I I

2. A method of producing filamentous products comprising the. steps ofstretching; in a direc tion'genrally longitudinally thereof, a wetfilarmentary bundle of web-like sheet structure com prising continuousfilaments in a plastic con dition mixed with continuous filaments in anelastic condition, collecting the sheet as such while stillwet and undertension in the form of a multiple-layered winding, serving the wind-'ing across its width, drying the relaxed winding' in the form ofv aband, and stretching the dried band out in the direction of its widthwhile permitting it to expand in thickness.

3. A method of producing filamentous products comprising the steps ofstretching, in a direction generally longitudinally thereof, a Wetfilamentary bundle of Web-like sheet structure comprising continuousfilaments in a plastic condition mixed with continuous filaments in an.

elastic condition, collecting the sheet' as such while still wet inrelaxed condition in the form of multiple-layered winding, severing thewinding across its width, drying the relaxed winding in the form of aband, and stretching the dried band out in-the direction of its widthwhile permitting it to expand in thickness,

4;. A method'of producing light-weight filamentous products comprisingthe steps concurrently forming in a common precipitating medium amixture of wet continuous filaments having different rates of settingup, associating said filaments in a common bundle of web-like sheetstructure, stretching the bundle in a direction generally longitudinallythereof while at theelo eat d tic? filaments when released. causesadditional wavizeergeee 1eastone -ofthe -=fiiamentsthereir'r'is-essentiel l y elastic in character-end at least=one oth'ez is still-essenti allyplastieeharaetezacollecting the sheet as sueh while stillwet in the --form---of a multiple-layered winding; severing the -windingaeross --itswidth, drying the relaxed winding inthedor-mof a band,- and:stretching :the dried: bandout in the-direction offiitswidth while:perm-itting 'it -t0 expand -in: thickness;

52 A) method of producing lighuweightdilae mentous: products compr-ising:the steps: tot-:3 con-1- ourrentlm forming. inat common precipitatingmedium mmixture of wet: continuousaxfilamente havingadifienentarates of:settingaup; associatingsaldz'filaments. in a: common ,:bundleeof;weblike sheetistructure, stretchingzthellbundle imd-aaedie reotion:generally longitudinally thereof while at; least :one :of the.filaments. therein; essentially?- elastic inlcharacter; end at: least.vone other still: essentially plastic. inicharactezz; colleetingthe;sheet; as sucmwhile ;sti1l.uwet:v andmnden tensiom intheiormot:a.mu1tiple-layened windinasevereing-itherminding;acrossnitsiwidth; drying the arelaxed winding-.imtheform of azbandbandvstnetehrn ethe drieduband; out innthe-i direetion:of, its width: Whilwpermittflng. it; to expand, inythlck ness.

6. A method of producing light-we'glitefilamenteus; products;comprising, the steps; ofiiconcugxentlyforming; in: a. commonprecipitating; mediumsasmixtune, of; wet. continuous; filaments havingid-ifferent rates of setting up, associatingsaiclefilamentstina..common; bundle, of. WQhEli-KQ: sheet; structure; stretching theybundlein a; die;- reetio'nz generallylongitudinally thereof. while-at;leasteoneloi the; filaments t therein is essentially elastie in;character and at least one othen-is. still; essentially plastic incharacter,- eolleeti'ngithe sheet-as such while still wet and ,in.relaxed com-(l dition invtheformuoi a multiple-layeredwinde ing,severing the winding ac tossits width, dry,- ing therxelaxed winding inthe, form of. a. band; andgstretching the dried bandw'lout intiomof-eits Width. whileipetmittingflit.tQeXPandJm thicknesses 'YLlTAemethod of: producing lightweight. filer. mentousvpmduets .comprisingthe.steps-. .of'c0n. curxently formingin a, common precipitatingmediums. mixture .of wetcontinuous.filaments; of. a, icogolymen of.,viny1,.chloride. and .vinyl acetate. haying difierent, rates ofsetting.,up,, associating said filamentscinma) common b,undle. ;of.web..-lil-ie sheet; steucture in a,v direction. stretching the bundle inafldirlectionz generally, longitudinally thezeoflwhile at. least oneoi-thetfilamentst therein is essentially elalstiein. charactenandatleastlnnem other is,sti1l essentially plastielintcharacter col-electing'r the sheet assuchwhile still wetandlunder tensioniin theformnofwaemultiplerlayenedewinde ing severing the winding ,across itswidth, dry, mg the relaixecl'wiridihgin the ,formpof a handy andstsetching the. ,driedmband. outin .themdinec; tionilofuitslwidth whilepermitting. .itto expend.

infthiekness 8h!method,.of; ,preducingaelighte-weight,filarmentions;:productpcomprising: the steps 50f:-c,on.-1-- currentlyforming a, comznom pnecipitalting;medium-:a;-mixtureof wet, continuous. filaments of aeeopolymee of"vinyl; chloride; andqvinyl acetate:

cemp isingfilaments; of largediametemanddile 70* meme; of: smallezj:diameter; which: set tupzmorex rapidly: than; the :1 larger: filaments;Y associating;

a: saidl'fila'ments-in ex common b'undle ili'a diiieetiiin generallylongitudinally =thereofi bf- Wen -like sheet stmeturerstnetehingthe-bundle whileet-leastwne of the 'small filaments theeeiIi-isessentiel'lWelzts''-- 51 tie- 121* 4 character and-at least? one of thelrge 1e stretching thedried 'band butr in tfie=difeetidn-=of= its widthwhile pemnitti-ng it-io-expand izi thiok nessw r 9-? mmethod iofproducing aalight weighfgfila mentous product comprisingthestps ofiassolike sheet structure a mixture ofawet continuous filements respondingdifferently to pla'stioizizig media; subecting ttie bundl'e'whil =-stillin th'e for-m1 of av-webdikesheet structure 'to-a plaistioiz ingxmediumwthen: stretching the bundl im-a 'dii-" reetimn general-1 y"longitucli'nally= thereofi whilestalll inlwebdike -form endwhile at'-l'east one filelment thereim is in aeplasticl: :cendition and? at;least? oneuother i filament i therein iS -ili a sub'stantiallifielastieaconditiony collecting the sheet whil' still wetiiasssuchezinntheform: of; a -multipleslayeped z winding; severing the 'win-dihg across-it's ewidtfitdrying therelaxed winding*iri th'e40mmof-euhieladiandsstretching thezdried band-out in thedii'ectiom of}: its;widthzzwhiles permitting: if}? tozexpandi in thickness;

10..,A-.:i.metl1od:i of: producing-:- a; light-weight?filamentousaproduct comprisingthe stps of asso stating in alzcommonfilamentary-bundle:-offlweh like.hheetfstnuctureeazmixture o wetBontiii-uons filaments ofrra'zcopolymer of fvinylohlol i'de' enr1vinsrhaeetate' which are: of d'rffeventisizes "and" thexeby: are.edifierentlyr: affecteda-by plastieizing'; med-le subj eatingztheebundleeto a plestitiizihg w medihm whilemeintaining itimslieet:formati'on';

stretching theimebelikexsheet im'w diPectiUnYgeH enallylongitudinally:memoir-while at least-"0211:-filamenttithenemzis;imaz'plastie conditronraml at least eoneaotherfilamentrthereiriaiaiheasubstane 4E5 tiellywelastimconditien;collecting-:5thewslieetziesr bandeoutdn:thegdirection; of: itswidtlirwh-ile perwmittingeit tozexpandjmthiokness.2

ROBEBTE'JZ TA: "OBI-r REEERENCESeGITEDp.

The -following references are 'of'-recordfin*the file -of this patent?UNITED. STATESePA-TENTS Nnmh'em Mme Dime?- 6G? 845658. 79? \WddetlMair:-'12'; 1907- 1,993,8fl? Kzoch't Mam--12; 1935 2;;165251 i Taylor.Jan. 12, 1937 211,558.93: Eisenhut etelteenfl Apr. 1851939; 21811353.;Boedding'haus Nova 21"," 1939? Taiylors; Aprz BUi-IQ L'G Certificate ofCorrection Patent N 0. 2,461,094 February 8, 1949 ROBERT J. TAYLOR It ishereby certified that errors appear in the printed specification of theabove numbered patent requiring correction as follows:

Column 6, line 50, for the word serving read severing; line 62, afterthe word wet insert and; line 63, after of insert a;l1ne 69, after stepsinsert of column 7, line 53, before stretching strike out in adirection;

and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case in thePatent Ofiice.

Signed and sealed this 20th day of December, A. D 1949.

THOMAS F. MURPHY,

Am'stant Uommz'm'oner of Patents.

